Maths

A manufacturer produces two Models of bikes – Model \mathbf{X} and Model \mathbf{Y}. Model \mathbf{X} takes 6 man-hours to make per unit, while Model Y takes 10 man-hours per unit. There is a total of 450 man-hour available per week. Handling and Marketing costs are Rs 2000 and Rs 1000 per unit for Models X and Y respectively. The total funds available for these purposes are Rs 80,000 per week. Profits per unit for Models \mathrm{X} and \mathrm{Y} are Rs 1000 and Rs 500 , respectively. How many bikes of each model should the manufacturer produce so as to yield a maximum profit? Find the maximum profit.

Solution: Let us take $\mathrm{x}$ an $\mathrm{y}$ to be the no. of models of bike produced by the manufacturer. From the question we have, Model $x$ takes 6 man-hours to make per unit Model $y$...

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A bag contains

    \[(2n+1)\]

coins. It is known that n of these coins has a head on both sides whereas the rest of the coins are fair. A coin is picked up at random from the bag and is tossed. If the probability that the toss results in a head is

    \[31/42\]

, determine the value of n.

Given, n coins are two headed coins and the remaining \[(n+1)\] coins are fair. Let  \[{{E}_{1}}\] : the event that unfair coin is selected \[{{E}_{2}}\] : the event that the fair coin is selected...

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An item is manufactured by three machines A, B and C. Out of the total number of items manufactured during a specified period,

    \[50%\]

are manufactured on A,

    \[30%\]

on B and

    \[20%\]

on C.

    \[2%\]

of the items produced on A and

    \[2%\]

of items produced on B are defective, and

    \[3%\]

of these produced on C are defective. All the items are stored at one godown. One item is drawn at random and is found to be defective. What is the probability that it was manufactured on machine A?

Let’s consider: \[{{E}_{1}}\] = The event that the item is manufactured on machine A \[{{E}_{2}}\] = The event that the item is manufactured on machine B \[{{E}_{3}}\] = The event that the item is...

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By examining the chest X ray, the probability that TB is detected when a person is actually suffering is

    \[0.99\]

. The probability of an healthy person diagnosed to have TB is

    \[0.001\]

. In a certain city,

    \[1\]

in

    \[1000\]

people suffers from TB. A person is selected at random and is diagnosed to have TB. What is the probability that he actually has TB?

Let \[{{E}_{1}}\] = Event that a person has TB \[{{E}_{2}}\] = Event that a person does not have TB And H = Event that the person is diagnosed to have TB. So, \[P({{E}_{1}})\text{ }=\text{...

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There are three urns containing

    \[2\]

white and

    \[3\]

black balls,

    \[3\]

white and

    \[2\]

black balls, and

    \[4\]

white and

    \[1\]

black balls, respectively. There is an equal probability of each urn being chosen. A ball is drawn at random from the chosen urn and it is found to be white. Find the probability that the ball drawn was from the second urn.

Given, we have \[3\] urns: Urn \[1\] = \[2\] white and \[3\] black balls Urn \[2\] = \[3\] white and 2 black balls Urn \[3\] = \[4\] white and \[1\] black balls Now, the probabilities of choosing...

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There are two bags, one of which contains

    \[3\]

black and

    \[4\]

white balls while the other contains

    \[4\]

black and

    \[3\]

white balls. A die is thrown. If it shows up

    \[1\]

or

    \[3\]

, a ball is taken from the Ist bag; but it shows up any other number, a ball is chosen from the second bag. Find the probability of choosing a black ball.

Let \[{{E}_{1}}\] be the event of selecting Bag \[1\] and \[{{E}_{2}}\] be the event of selecting Bag \[2\]. Also, let \[{{E}_{3}}\] be the event that black ball is selected Now,...

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A shopkeeper sells three types of flower seeds

    \[{{A}_{1}}\]

,

    \[{{A}_{2}}\]

and

    \[{{A}_{3}}\]

. They are sold as a mixture where the proportions are

    \[4:4:2\]

respectively. The germination rates of the three types of seeds are

    \[45%\]

,

    \[60%\]

and

    \[35%\]

. Calculate the probability (i) of a randomly chosen seed to germinate (ii) that it will not germinate given that the seed is of type A3, (iii) that it is of the type A2 given that a randomly chosen seed does not germinate.

Given that: \[{{A}_{1}}:\text{ }{{A}_{2}}:\text{ }{{A}_{3}}~=\text{ }4:\text{ }4:\text{ }2\] So, the probabilities will be \[P({{A}_{1}})\text{ }=\text{ }4/10,\text{ }P({{A}_{2}})\text{ }=\text{...

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Three bags contain a number of red and white balls as follows: Bag

    \[1:3\]

red balls, Bag

    \[2:2\]

red balls and

    \[1\]

white ball Bag

    \[3:3\]

white balls. The probability that bag i will be chosen and a ball is selected from it is

    \[\mathbf{i}/\mathbf{6},\text{ }\mathbf{i}\text{ }=\text{ }\mathbf{1},\text{ }\mathbf{2},\text{ }\mathbf{3}\]

. What is the probability that (i) a red ball will be selected? (ii) a white ball is selected?

Given: Bag \[1:3\] red balls, Bag \[2:2\] red balls and \[1\] white ball Bag \[3:3\]  white balls Now, let E1, E2 and E3 be the events of choosing Bag \[1\], Bag \[2\] and Bag \[3\] respectively and...

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An urn contains m white and n black balls. A ball is drawn at random and is put back into the urn along with k additional balls of the same colour as that of the ball drawn. A ball is again drawn at random. Show that the probability of drawing a white ball now does not depend on k.

Let’s consider A to be the event of having m white and n black balls \[{{E}_{1}}\] = First ball drawn of white colour \[{{E}_{2}}\] = First ball drawn of black colour \[{{E}_{3}}\]  = Second ball...

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Suppose that

    \[6%\]

of the people with blood group O are left-handed and

    \[10%\]

of those with other blood groups are left-handed

    \[30%\]

of the people have blood group O. If a left-handed person is selected at random, what is the probability that he/she will have blood group O?

Let’s assume \[{{E}_{1}}\] = The event that a person selected is of blood group O \[{{E}_{2}}\] = The event that the people selected is of other group And H = The event that selected person is left...

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A factory produces bulbs. The probability that any one bulb is defective is

    \[1/50\]

and they are packed in boxes of

    \[10\]

. From a single box, find the probability that (i) none of the bulbs is defective (ii) exactly two bulbs are defective (iii) more than

    \[8\]

bulbs work properly

Let’s assume X to be the random variable denoting a bulb to be defective. Here, \[n\text{ }=\text{ }10,\text{ }p\text{ }=\text{ }1/50,\text{ }q\text{ }=\text{ }1\text{ }\text{ }1/50\text{ }=\text{...

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A bag contains

    \[4\]

white and

    \[5\]

black balls. Another bag contains

    \[9\]

white and

    \[7\]

black balls. A ball is transferred from the first bag to the second and then a ball is drawn at random from the second bag. Find the probability that the ball drawn is white.

Let us consider  \[{{W}_{1}}\] and \[{{W}_{2}}\] to be two bags containing \[\left( 4W,\text{ }5B \right)\]and \[\left( 9W,\text{ }7B \right)\]balls respectively. Let us take \[{{E}_{1}}\] be the...

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In a dice game, a player pays a stake of Re

    \[1\]

for each throw of a die. She receives Rs

    \[5\]

if the die shows a

    \[3\]

, Rs

    \[2\]

if the die shows a

    \[1\]

or

    \[6\]

, and nothing otherwise. What is the player’s expected profit per throw over a long series of throws?

Let’s take X to be the random variable of profit per throw. As, she loses Rs \[1\] for giving any od \[2,4,5\]. So, \[P\left( X\text{ }=\text{ }-1 \right)\text{ }=\text{ }1/6\text{ }+\text{...

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Two dice are thrown together and the total score is noted. The events E, F and G are ‘a total of

    \[4\]

’, ‘a total of

    \[9\]

or more’, and ‘a total divisible by

    \[5\]

’, respectively. Calculate P(E), P(F) and P(G) and decide which pairs of events, if any, are independent.

If two dice are thrown together, we have n(S) = \[36\] Now, let’s consider: E = A total of \[4\text{ }=\text{ }\left\{ \left( 2,\text{ }2 \right),\text{ }\left( 1,\text{ }3 \right),\text{ }\left(...

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For a loaded die, the probabilities of outcomes are given as under:

    \[\mathbf{P}\left( \mathbf{1} \right)\text{ }=\text{ }\mathbf{P}\left( \mathbf{2} \right)\text{ }=\text{ }\mathbf{0}.\mathbf{2},\text{ }\mathbf{P}\left( \mathbf{3} \right)\text{ }=\text{ }\mathbf{P}\left( \mathbf{5} \right)\text{ }=\text{ }\mathbf{P}\left( \mathbf{6} \right)\text{ }=\text{ }\mathbf{0}.\mathbf{1}\text{ }\mathbf{and}\text{ }\mathbf{P}\left( \mathbf{4} \right)\text{ }=\text{ }\mathbf{0}.\mathbf{3}\]

. The die is thrown two times. Let A and B be the events, ‘same number each time’, and ‘a total score is

    \[10\]

or more’, respectively. Determine whether or not A and B are independent.

Given that a loaded die is thrown such that \[\mathbf{P}\left( \mathbf{1} \right)\text{ }=\text{ }\mathbf{P}\left( \mathbf{2} \right)\text{ }=\text{ }\mathbf{0}.\mathbf{2},\text{ }\mathbf{P}\left(...

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A manufacturer produces two Models of bikes – Model X and Model Y. Model X takes

    \[6\]

man-hours to make per unit, while Model Y takes

    \[10\]

man-hours per unit. There is a total of

    \[450\]

man-hour available per week. Handling and Marketing costs are Rs

    \[2000\]

and Rs

    \[1000\]

per unit for Models X and Y respectively. The total funds available for these purposes are Rs 80,000 per week. Profits per unit for Models X and Y are Rs

    \[1000\]

and Rs

    \[500\]

, respectively. How many bikes of each model should the manufacturer produce so as to yield a maximum profit? Find the maximum profit.

Let’s take x an y to be the number of models of bike produced by the manufacturer. From the question we have, Model x takes \[6\] man-hours to make per unit Model y takes \[10\] man-hours to make...

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A man rides his motorcycle at the speed of

    \[50\]

km/hour. He has to spend Rs

    \[2\]

per km on petrol. If he rides it at a faster speed of

    \[80\]

km/hour, the petrol cost increases to Rs

    \[3\]

per km. He has at most Rs

    \[120\]

to spend on petrol and one hour’s time. He wishes to find the maximum distance that he can travel. Express this problem as a linear programming problem.

Let’s assume the man covers x km on his motorcycle at the speed of \[50\]km/hr and covers y km at the speed of \[50\] km/hr and covers y km at the speed of \[80\] km/hr. So, cost of petrol =...

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A company manufactures two types of sweaters: type A and type B. It costs Rs

    \[360\]

to make a type A sweater and Rs

    \[120\]

to make a type B sweater. The company can make at most

    \[300\]

sweaters and spend at most Rs

    \[72000\]

a day. The number of sweaters of type B cannot exceed the number of sweaters of type A by more than 100. The company makes a profit of Rs

    \[200\]

for each sweater of type A and Rs

    \[120\]

for every sweater of type B. Formulate this problem as a LPP to maximize the profit to the company.

Let’s assume x and y to be the number of sweaters of type A and type B respectively. From the question, the following constraints are: \[360x\text{ }+\text{ }120y\le 72000\Rightarrow 3x\text{...

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A company manufactures two types of screws A and B. All the screws have to pass through a threading machine and a slotting machine. A box of Type A screws requires

    \[2\]

minutes on the threading machine and

    \[3\]

minutes on the slotting machine. A box of type B screws requires

    \[8\]

minutes of threading on the threading machine and

    \[2\]

minutes on the slotting machine. In a week, each machine is available for

    \[60\]

hours. On selling these screws, the company gets a profit of Rs

    \[100\]

per box on type A screws and Rs 170 per box on type B screws. Formulate this problem as a LPP given that the objective is to maximize profit.

Let’s consider that the company manufactures x boxes of type A screws and y boxes of type B screws. From the given information the below table is constructed: From the data in the above table, the...

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A firm has to transport

    \[1200\]

packages using large vans which can carry

    \[200\]

packages each and small vans which can take

    \[80\]

packages each. The cost for engaging each large van is Rs

    \[400\]

and each small van is Rs

    \[200\]

. Not more than Rs

    \[3000\]

is to be spent on the job and the number of large vans cannot exceed the number of small vans. Formulate this problem as a LPP given that the objective is to minimize cost.

Let us  consider x and y to be the number of large and small vans respectively. From the given information the below constrains table is constructed: Now, the objective function for minimum cost is...

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A manufacturer of electronic circuits has a stock of

    \[200\]

resistors,

    \[120\]

transistors and

    \[150\]

capacitors and is required to produce two types of circuits A and B. Type A requires

    \[20\]

resistors,

    \[10\]

transistors and

    \[10\]

capacitors. Type B requires

    \[10\]

resistors,

    \[20\]

transistors and

    \[30\]

capacitors. If the profit on type A circuit is Rs

    \[50\]

and that on type B circuit is Rs

    \[60\]

, formulate this problem as a LPP so that the manufacturer can maximize his profit.

Let x units of type A and y units of type B electric circuits be produced by the manufacturer. From the given information the below table is constructed: Now, the total profit function in rupees...

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